=SUMPRODUCT((C5:C65<"Ginny
cancelled")*(A5:A65<"")/(COUNTIF(A5:A65,A5:A65&"")))

"Watercolor artist" wrote in
message ...
if one of its cells is either null or blank?

=SUM(1/COUNTIF(A5:A65,A5:A65)*(C5:C65<"Ginny cancelled"))

Thanks.